Automatically-controlled oil burner



March 25 19369 L. I. ALDRICH fi fi I AuTmncALLY CONTROLLED on. BURNER Filed'ma 1, 1925 2 Sheets-Sheet 1 2 Sheets-Sheet 2 WW2 gm a March 25 1930: L. ALDRICH AUTOMATICALLY CONTROLLED OIL BURNER Filed May 1 1925 /z/aznesses Patented Mar. 25, 1930 LQYD r. amnion, oErEoRm, rnnnrors, nssreivon To PREFERRED on. BURNEBS, nm,

or anemia, rumors, a conroaarron 0E armors AUTOMATICALLY-CONTROLLED OE BURNER Application tiled May 1,

This invention relates to automatic control mechanism for domestic oil burners.

The object of the invention is in the provision of a high voltage control system for domestic fuel burners. I

Another object of the invention is in the provision of a high voltage control system for domestic'fuel burners, wherein the safety member is an electrically controlled thermostatic agent and is included in the high voltage circuit.

Still another object of the invention is in the provision of an automatic control system for domestic fuel burners, comprising a high voltage circuit, including a thermostatic safety element sensitive to combustion conditions. i

A further object of the invention is in the provision of a high voltage control sys term for domestic fuel burners, said control system including a thermal safety element which is included in saidhigh voltage circuit upon starting operation.

Yet another object of the invention is in the provision of a line voltage control systemfor domestic fuel burners, including the safety control element in a manner to prevent operation of the burner under other than normal conditions.

@ther objects will appear in connection with the specification and drawings, in

p which Fig. l is a diagrammatic view of the elec-' trical connections, includin a perspective, partially in' section, of the iiurner;

Fig. 2 is an enlarged diagrammatic showing, partially in section, disclosing the principle of operation of the burner; and

Fig. 3 is an enlarged detail of the latch on the safety switch.

Referring to the drawings, ll'have shown in Fig. 1 a general view of the domestic oil burner, as well as complete diagrammatical showing of the electrical control and safety mechanism therefor. The oil burner, per se,

has been described in detail in-my co-pending application, fierial No. 7 21,7 2 filed June 23,

1924. and in view of-the' fact that mypresent mechanism would be adaptable, with minor changes, to any of the well known types of returned through and angular direction to 1925. Serial II'o. 27,181.

domestic oil burners, only a general descrip-= tion of the oil burner will be given.

A co-pending application bearing Serial No. 27,182, filed May 1, 1925, contains substantially the same structural description as.

Sirocco fan. and attached thereto by suitable brackets is a liquid pressure air pump 16, said pump drive shaft 11. An oil pump 14 is located at the extremity of the common drive shaft,

and is also driven thereby. From the oiipump an oil line 15 leads to a venturi 16,. said 5 venturi also having connection 17 with the liquid pressure air pump. Disposed adjacent the venturi and in the oil line is a needle valve or fuel control member 18. Also adjacent the fuel pump is a pressure valve 19 and a fuel by-pass 20 to a fuel container or reservoir (not shown). A common fuel mixture tube 21- is carried from the venturi to the nozzle 22 disposed within or substantially within the combustion chamber of the furnace. The fuel discharge tube passes through the blast housing 23 from the fan member. A sump 24is located inthe fuel mixture discharge tube in such manner as to trap any unatomized fuel, the same bem the lead 25 a the li id pressure air. means for replenishing the pump. Angularly disposed vane members 26 are mounted in the end of the blast housing adjacent the combustion chamber, and immediately surrounding the nozzle 22, the same acting to deflect the blast from the fan in an opposite the cone of the discharging fuel 'inixture. An air inlet to the also being driven by common pum the same providing liquid fuel air pressure pump is provided in a downwardly disposed member 27, the same projecting into the sump or base of the burner. A diaphra member 28 is con-- nected to the air pressure pump and is operated thereby in such manner as tocontrolv v physical portions which make up the safety mechanism for the burner, as well as the ignition mechanism, in view of the fact that said electrical circuit includes and cooperates with said members. I my Included in the safety mechanism is a commonly called stack thermostat, the same derivin'g its name from the fact that it is locatedin the stack of the furnace, although this location has been used merely because of simplicity of'assembly, and the safety thermostat might well be located any place where it would be sensitive tolcombustion conditions within the furnace. This stack thermostat generally includes elements sensitive to temao perature conditions, as well as a mercury contact bulb B controlled by the movement of the thermostat. Thismercury bulb contains therein contact points later to bade.- scribed in the electrical circuit of the burner. as A pipe from the air pressure pump 13 leads to a solenoid valve member that is controlled by a coil 31 included in the electrical circuit of the burner, and later to be described. From the valve, a ressure tube 31 leads-to a diaphragm 32 sui ably attached to the fuel mixture tube of the burner. A bell crank lever 33;is pivotally mounted at 34 adjacent the diaphragm and is related to the diaphragm member in a manner to be operated by the same. The opposed end 35 of the lever is connected to the ignition or sparking member of the nozzle 22, said sparking member includingthe two insulated electrodes 37 the same bei .disposed within the blast housing and sli ably mounted in the bearings '38 and 39. The ends of the electrodes project through the angularly disposed vanes 26 and when in an operative position, into the cone of the discharging fuel mixture. These electrodes, as said before, have movement translated to them through the lever 33 controlled by the diaphragm and are adapted to be withdrawn to a rearward or inoperative position where the sparking ends of the elecco trodes will'rest upon parts of the vane members. A coil spring 40 exerts a pressure upon the bell crank, normally holding the electrodes in rearward position, but expansion of the diaphragm overcomes same and forces 65 the electrodes forward to a sparking posistreaosa open the smaller valve 42. This action permits release of the pressure in the tube to the diaphragm 32 and collapse thereof after closing of the solenoid valve 30.

Having described the physical parts of my domestic fuel burner, I now come to the electrical portions and the circuits included therein; 7

As is well known in the art, domestic fuel burnersrefer mainly to oil burners adaptable to house installations or to any class of installation wherein automatic control of the burner is desired. In the present instance, as in all domestic fuel burners, a thermostat of well known design, is located in any desirable portion of the dwelling to be heated, and automatically controls the operation of the burner. The thermostat in the present instance'is shown at T and is of the so-called high voltage type, meaning that it-is adapted to receive the normal line voltage, usually 11'() volts. Tracing the electrical circuit in 'Fig. 1, wherein a diagram of same is shown, we find the 110 volt wire 100 from the switch 105 passing through the room thermostat T, and thence to the safety switch S, which in the present instance is a trip switch controlled by a thermal member 49 wound with a resistance coil 50. It might be said at this time that the safety switch once thrown by the thermal member, must be manually reset before the burner can resume activity. The safety switch S comprises a contactstri 46 fastened to a pivoted insulated plate 47 that normally maintains the 110 volt circuit closed, butadapted to open the circuit when frictional latch member 48 is actuated by the raising of the thermal strip 49 induced by the heat caused by the resistance coil 50. 0bviously, the cooling of the thermal member and movement to its lowered position is necessary before the switch can be manually reset.

Before completing the description of the electrical circuit, the detail description of the switch mechanism controlling the various operations will be given. An insulated panel 7 5 contains a movable plate 76 thereon, which operates the switch 102 which closes the circuit only when the motor 10 is running. .A, short circuit switch is shown at 104 on the same panel 75, and closes the circuit only when the motor is running. The switch 103 is. located on the lower sideof thepanel 75 and closes an electrical circuit only when the burneror'motor is idle. The insulated plate 76, or rather the movement thereof, is controlled by the action of the above described diaphragm 28 through the levers 77, 78 and 79. As above described, the diaphragm 28, or rather the action thereof, is controlled by the operation of the burner and more directly from the pressure raised in the liquid fuel air pressure pump 13. A connection which will be referred to as 111, leads from the contact on the right side of the mercury bulb B in the stack thermostat to a plural terminal Y. Another electrical connection, referred to as 112, leads from the left hand side of the mercury bulb in the stack thermostat to the short circuiting switch 104. The third electrical connection 113 in the stack thermostat leads from both sides of the mercury bulb C, to a point 113 on the return electrical circuit wire 115, said wire being on the other side of the high voltage circuit and leading to the main or service switch 105. Another electrical circuit leads from the plural terminal member X, through the wire 116 to a formal 110 volt spark coil 117, the circuit being completed through the wire 118 to another plural terminal member Y, and the circuit continuing through wire 111 to the stack thermostat and thence through the common wire 113 to the other side of the 110 voltcircuit. This is a temporary circuit for ignition purposes and is broken when combustion conditions have heated the stack thermostat and moved same so that the circuit is broken in the mercury bulb B. Wires 119 and 120 lead from the spark coil to the electrodes in the spark ignition mechanism.

Still another circuit leads from the plural terminal member X, through the wire 122 to the coil 31, operating the solenoid which is actually the valve 30 in the pressure line between the liquid air compressor and the diaphragm 32, operating the lever 33, which controls movement of the electrodes of the spark. This structure has been described in detail above. The circuit is completed through the wire 124, which leads to the plural terminal Y, thence through the wire 111 to the stack thermostat and 1s finally completed through common wire 113 and the return wire 115 of the 110 volt circuit.

This is a temporary circuit for operating the spark withdrawal mechanism, and is controlled in exactl the same manner as the spark ignition mem er, namely by movement of the stack thermostat, induced by combus tion conditions.

Althou h the actual wiring, included in the electrical circuits, has been described and numbered, nevertheless, a clearer understanding of said circuits will be ained by describing said circuits in connection with the operation of the automatically controlled burner.

As said before, the present burner is automatically controlled by a. high voltage thermostat T located in a desired placein the dwelling to be heated. We will assume that the burner is idle; that the temperature of the dwelling has lowered to a point where the house tremostat T has been actuated, and the 110 volt or line circuit closed therethrough.

This movement of the house thermostat to a closed, or rather on position, permits the 110 volt current to pass to the motor through the wire 100, which first goes to the safety switch S, then through wire 125 to the plural terminal member 0, thence through wire 126 to the motor, whereupon the motor is immediately energized.

Tracing the 110 volt circuit, immediately upon the energizing of the motor, we find that said current passes from the motor through the wire 127 to the terminal Z, passing through the wire 128 to the heat coil 50, thence to a wire 129, thence through the contact plate on the switch 103, which is closed for a short time immediately after the initial energizing of the motor, said current passing thereafter through the wire 111 of the right hand or cold side C of the stack thermostat. This current returns through the common wire 113 to a point 113 where it connects with the other side, namely the wire 115 of the 110 volt circuit.

It mightbe said at this time relative to the stack thermostat described as B, that for the purpose of clearness in description, merely the mercury contact bulb thereon has been disclosed. It might be added that this mercury contact bulb is controlled by thermal elements disposed in a manner to be sensitive to combustion conditions, and with relation to the present description of operation, we have called the right side of the mercury bulb the cold side, in view of the fact that this bulb will have the circuit completed through the wires 111 and 113, when the combustion chamber is at low temperature, this being namely while theburner is idle, and for a. temporary period after the commencement of operation of the burner.

Continuing the operation of the burner, as well as the description of the electrical circuits, we find that the main electrical circuit was completed immediately upon the throwing of the room thermostat. However, simultaneously with the completion of the above described circuit, the following electrical circuits were energized.

Starting at the plural terminal member X,

we find the spark ignition circuit which asses through the wire 116 to the spark coil 117 and returns from the spark coil through the wire 118 to the plural terminal Y, thence through the wire 111 to the cold side of the mercury bulb in the stack thermostat, thence returning through the common wire 113, in the stack thermostat, through said wire, and finally connecting with the return wire 115 in the 110 volt circuit. In other words, upon the initial energizing of the 110 volt circuit, the spark coil is simultaneously ener 'zed through the wires 119 and 120 and spar 'ng tau - at the contact points of the electrodes results,

the same providing the means for igniting the-projected fuel mixture, which is discharging durin the operation of the burner.

At thls time it is thought best to bring out the temporary action of the sparking mechanism, when it can be plainly seen that upon a rise in temperature in the combustion chamber, the stack'thermostat will be moved with a similar action of the mercurybulb, whereupon the circuit will be opened 'between the wires 111 and 113, and de-energizing of the sparking circuit will immediately take place. It might be added, however, that prior to the de-energizing of the spark coil, other electrical actions take place, the same being as follows. Again, and simultaneously with the initial energizing of the 110 volt circuit, and sarting at the plural terminal X, we find the wire 122 carrying the electrical circuit therethrough to the coil 31 controlling the operation of the solenoid valve 30, said current returning from the coil through the line 124 to the plural terminal member Y, thence through the wire 111 to the cold side of the stack thermostat, or rather, mercury bulb, then passing through the common Wire 113, to the return wire 115 of the 110 volt circuit.

Again, we find merely a temporary circuit controlled exactly as in the case of the spark ignition mechanism by the operation of the stack thermostat, which upon arise in tem perature in the combustion chamber, moves the mercury contact bulb to a hot position, and thereby opens the circuit in the bulb between the wires 111 and 113.

At this time, relative to the mechanism for projecting and withdrawing the electrodes of the s ark ignition mechanism, it might be said t at upon the energizing of the coil 31 surrounding the solenoid valve 30, said valve is raised, and pressure from the air pressure pump is permitted to pass through the tube 31, to the diaphragm 32, whereupon the bell crank lever 33 is moved to project the electrodes to a point within the cone of the projected fuel mixture.

From the above description, we find that sparking is taking place across the contact oints of these electrodes at this time and ence ignition of the projected fuel mixture takes place in this manner. -This sparking takes place continuously with the solenoid valve action, inasmuch as both are controlled by the movement of the stack thermostat and hence both projection of the electrodes into the zone of ignition, as well as sparking of the electrodes will continue until the temperature in .the combustion chamber has risen to a point where the stack thermostat will be operated to open theelectrical circuit there-- through, hence de-energizing the spark coil- 117, releasing the coil 31 surrounding the solenoid valve and prohibiting the passage of air under pressure to inflate the diaphragm.

afreaoea Collapse of the diaphragm, assisted by the o ening of the small valve 42 and the tension olthe spring 40, against the bell crank, results in the immediate withdrawal of the electrodes to a point where the contact portions thereof abut the angularly disposed vanes surroundin the nozzle. This withdrawal of the electro es against thevanes, both due to the collapse of the diaphragm and the action of the spring, automatically cleanses said electrodes of any carbon or other deposits there- Continuing the description of the operation of the burner in connection with the electrical circuits therefor, it will be necessary to go back to a time g'ust after the room thermostat has operated and the commencement of burner activity. We have described the immediate electrical circuit that was completed. Now, continuing the operation of the burner, we find that very shortly a pressure is created within the air pressure pump 13, that said pressure is transmitted to the diaphragm 28, said diaphragm, through the levers 7 78 and 79, likewise transmitting movementtgo portion 104 thereof.

It might be said at this time that because of the fact that the contact is made between the movable contact member 102 and the stationary contact 102 prior to the release of the movable contact member 103 from point 103', no arcing of the contacts-is possible, due to the changing circuits. After the release of the movable contact member 103, the circuit passes through the contact made previously by the movement of the movable contact 102 with the stationary contact 102 thence through the wire 115, which is the return wire of the 110 volt circuit. This operation of the above described movable switch member 102 completes a shorter electrical circuit for the electric motor and short-circuits out the portion of the. same circuit which previously went through the stack thermostat.

This operation, or rather slight changing, of

ment of the short circuiting switch 10 1, completes a circuit not yet made through the hot side of the stack thermostat, namely, through wires 113 and 112. This contact 1s made at this time and said circuit closed for the reason that it is getting ready for the movement of the mercury bulb to the hot position and preparing to cut out the current from going through the resistance or heat coil 50 after the stack thermostat has operated.

Now, when the temperature in the combustion chamber is such that the stack thermostat actually moves, the mercury bulb is tilted and the electrical circuits to the solenoid valve 31 and the spark ignition mechanism are opened, and at the same time the circuit through the short circuiting switch 104 is completed, thereby permitting the current which formerly went through the wire 128, to flow through wire 112 to the mercury bulb, then out the common wire 113, and finally to the return 110 volt wire 115.

The burner is now operating in a normal manner, and the dwelling is being heated. When the temperature of the dwelling has reached a point where the room thermostat is operated to shut the burner off, then cessation of the burner is occasioned by the (opening of the 110 volt circuit, due to the tilting of the mercury contact bulb in the room thermostat. Upon the cessation of operation of the burner, there follows naturally a lower ing of the temperature inthe combustion chamber, with the consequent movement of the stack thermostatto a cold position, namely,'to the full line position shown in Fig. 1. We now find the burner and electrical circuits in exactly the same position in which we started our description of the aeration.

It will be obvious from the above that upon either failure of initial ignition or failure of combustion conditions thereafter during burner activity, that the bulb in the stack thermostat will .either be in or move to the cold position, whereupon after a determined time, the resistance coil 50 will heat up the thermal member 49, which will rise, release the latch on the safety switch, hence opening the switch and stopping burner activity until manually reset.

What I claim is:

1.; In combination with an electric motor driven fuel burner, an ignition member, automatic control means therefor comprising a thermostat, a starting switch controlled by combustion conditions, an electrically operated switch actuating mechanism, a switch requiring manual reset adapted to be operated thereby, a high voltage circuit including the electric motor, thermostat, combustion switch and electrically operated switch actuating mechanism, a circuit changing mechanism comprising a switch member completing the starting circuit through the above named members, a second switch adapted to complete a shorterelectrical circuit, including the motor, prior to the opening of the first named switch and ending the movement of the combustion switch, and a third switch in a second circuit through the combustion switch adapted to close prior to the movement of said combustion switch.

2. In combination with an electric motor driven fuel burner, an ignition member, automatic control means therefor comprising a thermostat, a switch controlled by combustion conditions, an electrically operated switch actuating mechanism, a switch requiring manual reset adapted to be operated thereby, a high voltage starting circuit including said motor, thermostat, combustion switch and electrically operated switch 2:- tuating mechanism, and circuit controlling mechanism comprising a switch member initially completing the starting circuit and automatic means controlled by burner operation for opening same substantially immediately after initial completion, and a second switch in a second circuit through the combustion switch adapted to close prior to the opening of the said first named switch.

Signed at Peoria, Peoria County, Illinois, this 8th day of April, A. D. 1925.

V LOYD I, ALDRICH. 

